Performing Message Payload Processing Functions In A Network Element On Behalf Of An Application

ABSTRACT

A method is disclosed for performing message payload processing functions in a network element on behalf of an application. According to one aspect, a network element intercepts data packets comprising network layer or transport layer headers having an address of a destination which destination differs from the network element. The network element determines whether information contained in layer  2 - 4  headers of the data packet satisfies specified criteria. If the information satisfies the specified criteria, the network element directs the data packets to a blade of the network element that performs processing based on an application layer message at least partially contained in the data packets. If the information does not satisfy the specified criteria, the network element forwards the data packets towards the destination without sending them to the blade.

CLAIM OF PRIORITY

This application claims domestic priority under 35 U.S.C. §120 as aContinuation of prior U.S. patent application Ser. No. 11/005,978, filedon Dec. 6, 2004, the entire contents of which are hereby incorporated byreference as if fully set forth herein.

RELATED APPLICATIONS

This application is related to U.S. patent application Ser. No.10/991,792, entitled “PERFORMING MESSAGE AND TRANSFORMATION ADAPTERFUNCTIONS IN A NETWORK ELEMENT ON BEHALF OF AN APPLICATION” (AttorneyDocket No. 50325-0911), by Pravin Singhal, Qingqing Li, JuzarKothambalawa, Parley Van Oleson, Wai Yip Tung, and Sunil Potti, filed onNov. 17, 2004; and U.S. patent application Ser. No. 10/997,616, entitled“CACHING CONTENT AND STATE DATA AT A NETWORK ELEMENT” (Attorney DocketNo. 50325-0917), by Alex Yiu-Man Chan, Snehal Haridas, and Raj De Datta,filed on Nov. 23, 2004; the contents of which are incorporated byreference in their entirety for all purposes as though fully disclosedherein.

FIELD OF THE INVENTION

The present invention generally relates to network elements, such asswitches and routers, in computer networks. The invention relates morespecifically to a method and apparatus for performing message payloadprocessing functions in a network element on behalf of an application.

BACKGROUND

The approaches described in this section could be pursued, but are notnecessarily approaches that have been previously conceived or pursued.Therefore, unless otherwise indicated herein, the approaches describedin this section are not prior art to the claims in this application andare not admitted to be prior art by inclusion in this section.

In a business-to-business environment, applications executing oncomputers commonly communicate with other applications that execute onother computers. For example, an application “A” executing on a computer“X” might send, to an application “B” executing on a computer “Y,” amessage that indicates the substance of a purchase order.

Computer “X” might be remote from computer “Y.” In order for computer“X” to send the message to computer “Y,” computer “X” might send themessage through a computer network such as a local area network (LAN), awide-area network (WAN), or an inter-network such as the Internet. Inorder to transmit the message through such a network, computer “X” mightuse a suite of communication protocols. For example, computer “X” mightuse a network layer protocol such as Internet Protocol (IP) inconjunction with a transport layer protocol such as Transport ControlProtocol (TCP) to transmit the message.

Assuming that the message is transmitted using TCP, the message isencapsulated into one or more data packets; separate portions of thesame message may be sent in separate packets. Continuing the aboveexample, computer “X” sends the data packets through the network towardcomputer “Y.” One or more network elements intermediate to computer “X”and computer “Y” may receive the packets, determine a next “hop” for thepackets, and send the packets towards computer “Y.”

For example, a router “U” might receive the packets from computer “X”and determine, based on the packets being destined for computer “Y,”that the packets should be forwarded to another router “V” (the next“hop” on the route). Router “V” might receive the packets from router“U” and send the packets on to computer “Y.” At computer “Y,” thecontents of the packets may be extracted and reassembled to form theoriginal message, which may be provided to application “B.” Applications“A” and “B” may remain oblivious to the fact that the packets wererouted through routers “U” and “V.” Indeed, separate packets may takeseparate routes through the network.

A message may be transmitted using any of several application layerprotocols in conjunction with the network layer and transport layerprotocols discussed above. For example, application “A” may specify thatcomputer “X” is to send a message using Hypertext Transfer Protocol(HTTP). Accordingly, computer “X” may add HTTP-specific headers to thefront of the message before encapsulating the message into TCP packetsas described above. If application “B” is configured to receive messagesaccording to HTTP, then computer “Y” may use the HTTP-specific headersto handle the message.

In addition to all of the above, a message may be structured accordingto any of several message formats. A message format generally indicatesthe structure of a message. For example, if a purchase order comprisesan address and a delivery date, the address and delivery date may bedistinguished from each other within the message using messageformat-specific mechanisms. For example, application “A” may indicatethe structure of a purchase order using Extensible Markup Language(XML). Using XML as the message format, the address might be enclosedwithin “<address>” and “</address>” tags, and the delivery date might beenclosed within “<delivery-date>” and “</delivery-date>” tags. Ifapplication “B” is configured to interpret messages in XML, thenapplication “B” may use the tags in order to determine which part of themessage contains the address and which part of the message contains thedelivery date.

Often, though, different applications are designed to use differentapplication layer protocols to send and receive messages. For example,application “A” might be designed to send messages using only HTTP, butapplication “B” might be designed to receive messages using only FileTransfer Protocol (FTP), another application layer protocol.Furthermore, different applications may be designed to use differentmessage formats to format and interpret messages. For example,application “A” might be designed to format messages using only XML, butapplication “B” might be designed to interpret messages using onlyElectronic Data Interchange (EDI).

Usually, it is not practical or even possible to design or update anapplication so that the application can converse with other applicationsusing all possible message formats and application layer protocols. Somemessage formats and application layer protocols may be proprietary andnot publicly disclosed. Some message formats and application layerprotocols may be relatively new and obscure. Some message formats andapplication layer protocols may be so old as to be considered generallyobsolete.

In order to reduce the amount of application modification required toallow an application to converse with other applications that might usedifferent message formats and/or application layer protocols,intermediary network elements separate from such applications may bedesigned to receive messages, “translate” the messages, and then sendthe messages. This translation may be achieved by looking for aspecified bit pattern beginning at a specified bit location in a packet,and then altering bits at the specified bit location if the specifiedbit pattern is found. For example, a network appliance “J” might bedesigned to receive messages that have been sent using HTTP and sendthose messages using FTP instead. For another example, a networkappliance “K” might be designed to receive messages that are in XMLformat and translate those messages into EDI format. Thus, ifapplication “A” sends messages in XML using HTTP, and application “B”receives messages in EDI using FTP, then application “A” can beconfigured so that messages that application “A” normally would addressto application “B” are addressed to network appliance “J” instead. Thenetwork administrator can configure network appliance “J” to sendmessages to network appliance “K,” and the network administrator canconfigure network appliance “K” to send messages to application “B.”

Unfortunately, this approach requires a lot of effort from the networkadministrator. As the number of possible different application layerprotocols and message formats used by communicating applicationsincreases, the number of network appliances and paths between thosenetwork appliances rises dramatically. For each pair of sending andreceiving applications, a network administrator following this approachmust configure the applications and network appliances involved toensure that the messages will follow the correct path through therelevant network appliances. Thus, if each of applications “A,” “B,”“C,” “D,” and “E” needed to communicate with each other, the networkadministrator following this approach might need to configure 25different “paths” of one or more network appliances each. Asapplications are added, removed, and modified, the network administratormay need to add and/or remove certain network appliances from certainpaths between application pairs. When many applications are involved,the burden can be more than most network administrators can bear.

Additionally, if multiple paths are configured to contain the samenetwork appliance, then the network appliance may become a bottleneckthat degrades network performance.

Thus, this “pair-wise path configuration” approach is impractical whenapplied to systems in which large numbers of diverse applicationscommunicate. A more practical technique for allowing a multitude ofdiverse applications to communicate is needed.

Furthermore, existing intermediary network elements are limited in thekinds of processing that those network elements can perform on packets,and in the kinds of actions that those network elements can performrelative to packets. Typically, an existing intermediary network elementperforms only a single specialized operation relative only to datapackets that possess matching parameters in those data packets' headers.Both the parameters and the operation are typically fixed and cannot becustomized by an end user. A technique for allowing a greater number andvariety of customizable operations to be performed relative to dataflows is needed.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements and in which:

FIG. 1 is a block diagram that illustrates an overview of one embodimentof a system in which one or more network elements perform messagepayload processing functions on behalf of an application;

FIG. 2 depicts a flow diagram that illustrates an overview of oneembodiment of a method of performing message payload processingfunctions at a network element on behalf of a client application;

FIGS. 3A-B depict a flow diagram that illustrates one embodiment of amethod of performing message payload processing functions at a networkelement on behalf of an application;

FIG. 4 depicts a sample flow that might be associated with a particularmessage classification;

FIG. 5 is a block diagram that illustrates a computer system upon whichan embodiment may be implemented;

FIG. 6A is a block diagram that illustrates one embodiment of a routerin which a supervisor blade directs some packet flows to an AONS bladeand/or other blades;

FIG. 6B depicts a flow diagram that illustrates one embodiment of amethod of filtering packets for which message level processing is to beperformed;

FIG. 7 is a diagram that illustrates the various components involved inan AONS network according to one embodiment;

FIG. 8 is a block diagram that depicts functional modules within anexample AONS node;

FIG. 9 is a diagram that shows multiple tiers of filtering that may beperformed on message traffic in order to produce only a select set oftraffic that will be processed at the AONS layer;

FIG. 10 is a diagram that illustrates the path of a message within anAONS cloud according to a cloud view;

FIG. 11A and FIG. 11B are diagrams that illustrate a request/responsemessage flow;

FIG. 12A and FIG. 12B are diagrams that illustrate alternativerequest/response message flows;

FIG. 13 is a diagram that illustrates a one-way message flow;

FIG. 14 is a diagram that illustrates alternative one-way message flows;

FIG. 15A and FIG. 15B are diagrams that illustrate a request/responsemessage flow with reliable message delivery;

FIG. 16 is a diagram that illustrates a one-way message flow withreliable message delivery;

FIG. 17 is a diagram that illustrates synchronous request and responsemessages;

FIG. 18 is a diagram that illustrates a sample one-way end-to-endmessage flow;

FIG. 19 is a diagram that illustrates message-processing modules withinan AONS node;

FIG. 20 is a diagram that illustrates message processing within AONSnode;

FIG. 21, FIG. 22, and FIG. 23 are diagrams that illustrate entitieswithin an AONS configuration and management framework; and

FIG. 24 is a diagram that illustrates an AONS monitoring architecture.

DETAILED DESCRIPTION

A method and apparatus for performing message payload processingfunctions in a network element on behalf of an application is described.In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present invention. It will be apparent, however, toone skilled in the art that the present invention may be practicedwithout these specific details. In other instances, well-knownstructures and devices are shown in block diagram form in order to avoidunnecessarily obscuring the present invention.

Embodiments are described herein according to the following outline:

-   -   1.0 General Overview    -   2.0 Structural and Functional Overview    -   3.0 Implementation Examples        -   3.1 Multi-Blade Architecture        -   3.2 Performing Message Payload Processing Functions At A            Network Element        -   3.3 Action Flows        -   3.4 Filtered Processing        -   3.5 AONS Examples            -   3.5.1 AONS General Overview            -   3.5.2 AONS Terminology            -   3.5.3 AONS Functional Overview            -   3.5.4 AONS System Overview            -   3.5.5 AONS System Elements            -   3.5.6 AONS Example Features            -   3.5.7 AONS Functional Modules            -   3.5.8 AONS Modes of Operation            -   3.5.9 AONS Message Routing            -   3.5.10 Flows, Bladelets™, and Scriptlets™            -   3.5.11 AONS Services            -   3.5.12 AONS Configuration and Management            -   3.5.13 AONS Monitoring            -   3.5.14 AONS Tools    -   4.0 Implementation Mechanisms—Hardware Overview    -   5.0 Extensions and Alternatives

1.0 General Overview

The needs identified in the foregoing Background, and other needs andobjects that will become apparent for the following description, areachieved in the present invention, which comprises, in one aspect, amethod for performing message payload processing functions in a networkelement on behalf of an application. According to one embodiment, thenetwork element receives user-specified input that indicates aparticular message classification. The network element also receives oneor more data packets. Based on the data packets, the network elementdetermines that an application layer message, which is collectivelycontained in payload portions of the data packets and which is directedto the application, matches the particular message classification. Thenetwork element processes at least a portion of the message byperforming, relative to at least the portion of the message and onbehalf of the application, one or more actions that are (a) specified inthe user-specified input and (b) associated with the particular messageclassification.

According to one embodiment, processing the portion of the applicationlayer message comprises conceptually separating the contents of theapplication layer message from the remainder of the one or more datapackets and inspecting and interpreting the contents in a manner that isbased on semantics associated with the contents. This kind ofinspection, which is more fine-grained than packet-level inspection, maybe referred to as “deep content inspection.” For example, each part of amulti-part (MIME) message may be separately interpreted and inspectedbased on the semantics associated with that part. For example, if a partof a multi-part message is a JPEG image, then that part is inspectedbased on JPEG semantics; if a part of a multi-part message is an XMLdocument, then that part is inspected based on XML semantics; otherparts may be inspected based on different semantics. The distinctcomponents of a message are understood by the semantics associated withthat message.

Because the network element can perform any required “translation” ofmessages contained in payload portions of data packets that the networkelement receives, the applications that send and receive the messages donot need to be modified to perform the translations themselves. Theapplications that send and receive the messages can do so without havingany “awareness” that those messages are being modified (given that atrust relationship exists between the application and the networkelement for security reasons). Applications can communicate with eachother as though each other application communicated using the samemessage format and application layer protocol.

Furthermore, because a single network element that is intermediate tomultiple client and server applications can be configured, viauser-specified input, to match different data packet flows to differentuser-specified message classifications that are associated withdifferent user-specified actions, the selective placement of specializednetwork appliances within certain network administrator-selected networkpaths becomes unnecessary. A single network element can perform all ofthe actions that would otherwise be performed by multiple specializednetwork appliances. For example, the network element may be a networkrouter or a switch that would already be performing routing functionswithin the network; thus, using the approach described herein, thenumber of intermediate network elements sitting between a client andserver application would not need to be increased. For another example,the network element may be a network appliance and/or a device that isattached or connected to a switch or router and that performs OSI Layer2 and above processing, including packet- and message-level processing.

In other aspects, the invention encompasses a computer apparatus and acomputer-readable medium configured to carry out the foregoing steps.

2.0 Structural and Functional Overview

FIG. 1 is a block diagram that illustrates an overview of one embodimentof a system 100 in which one or more of network elements 102, 104, 106,and 108 perform message payload processing functions on behalf of anapplication. Network elements 102, 106, and 108 may be proxy devices,for example. Network element 104 may be a network router or a switchsuch as router 600 depicted in FIG. 6 below, for example.

Client application 110 is coupled communicatively with network element102. A server application 112 is coupled communicatively to networkelement 106. A server application 114 is coupled communicatively tonetwork element 108. Each of client application 110 and serverapplications 112 and 114 may be a separate computer. Alternatively, eachof client application 110 and server applications 112 and 114 may be aseparate process executing on separate computers.

Network elements 102 and 104 are coupled communicatively with a network116. Network elements 104 and 106 are coupled communicatively with anetwork 118. Network elements 104 and 108 are coupled communicativelywith a network 120. Each of networks 116, 118, and 120 is a computernetwork, such as, for example, a local area network (LAN), wide areanetwork (WAN), or internetwork such as the Internet. Networks 116, 118,and 120 may contain additional network elements such as routers.

In one embodiment, client application 110 addresses messages to serverapplications 112 and 114, and network elements 102, 104, 106, and 108intercept the data packets that contain the messages. In an alternativeembodiment, client application 110 explicitly addresses messages tonetwork element 102. Network elements 102, 104, 106, and 108 assembleone or more data packets to determine at least a portion of a messagecontained therein. Based on the message, network elements 102, 104, 106,and 108 perform one or more actions. Examples of some of these actionsare described in further detail below.

FIG. 2 depicts a flow diagram 200 that illustrates an overview of oneembodiment of a method of performing message payload processingfunctions at a network element on behalf of a client application. Such amethod may be performed, for example, by any of network elements 102,104, 106, and 108.

In block 202, a network element receives user-specified input. Theuser-specified input indicates a message classification and one or moreactions that are associated with the message classification. Forexample, network element 104 may receive such user-specified input froma network administrator. The message classification defines a categoryor class of messages. For example, all purchase orders might belong tothe same message classification. Messages that satisfy user-specifiedcriteria or rules associated with the message classification belong tothe message classification, while messages that do not satisfy thesecriteria or rules do not belong to the message classification.

In block 204, the network element receives one or more data packets. Forexample, network element 104 may intercept one or more data packets thatare destined for server application 112. For another example, networkelement 102 may receive one or more data packets that are destined fornetwork element 102. Network element 102 is capable of determiningapplication layer message boundaries, so, in one embodiment, networkelement 102 may perform operations (as described below) on anapplication layer message contained in a stream, or portions thereof,even if network element 102 has not yet received all of the data packetsthat contain all of the portions of the application layer message.

In block 206, based on the data packets, it is determined that anapplication layer message collectively contained in payload portions ofthe data packets belongs to the particular message classification. Forexample, network element 104 may assemble at least some of the datapackets. Network element 104 may inspect the contents of the payloadportions of the assembled data packets to determine at least a portionof an application layer message that client application 110 is trying tosend. The message may be, for example, a purchase order formattedaccording to XML and transmitted using HTTP. As such, the message maycontain HTTP and XML headers. Based on the message content and/orinformation in the data packet headers, network element 104 maydetermine that the message belongs to the particular messageclassification indicated in the user-specified input. For example,network element 104 may determine, based on a portion of the message,that the message is a purchase order.

In block 208, at least a portion of the message is processed via theperformance, relative to at least the portion of the message, of theactions that are associated with the particular message classification.For example, in response to determining that the message belongs to the“purchase order” message classification, network element 104 may performone or more specified actions that are associated with the “purchaseorder” message classification. The specified actions may include, forexample, modifying the message's format (e.g., from XML to EDI) andsending the message toward server application 112 using a differentapplication layer protocol (e.g., FTP) than the protocol that clientapplication 110 used to send the message. Examples of other possibleactions are described below.

3.0 Implementation Examples

3.1 Multi-Blade Architecture

According to one embodiment, an Application-Oriented Network Services(AONS) blade in a router or a switch performs the actions discussedabove. FIG. 6A is a block diagram that illustrates one embodiment of arouter 600 in which a supervisor blade 602 directs some of packet flows610A-B to an AONS blade and/or other blades 606N. Router 600 comprisessupervisor blade 602, AONS blade 604, and other blades 606A-N. Each ofblades 602, 604, and 606A-N is a single circuit board populated withcomponents such as processors, memory, and network connections that areusually found on multiple boards. Blades 602, 604, and 606A-N aredesigned to be addable to and removable from router 600. Thefunctionality of router 600 is determined by the functionality of theblades therein. Adding blades to router 600 can augment thefunctionality of router 600, but router 600 can provide a lesser degreeof functionality with fewer blades at a lesser cost if desired. One ormore of the blades may be optional.

Router 600 receives packet flows such as packet flows 610A-B. Morespecifically, in one embodiment, packet flows 610A-B received by router600 are received by supervisor blade 602. Supervisor blade 602 maycomprise a forwarding engine and/or a route processor such as thosecommercially available from Cisco Systems, Inc. In an alternativeembodiment, router 600 comprises one or more network I/O modules thatmay comprise a forwarding engine; in such an alternative embodiment, theoperations described below as being performed by supervisor blade 602are performed instead by a forwarding engine that is not situated withinsupervisor blade 602, so that packets may be forwarded to AONS blade 604without ever going through supervisor blade 602.

In one embodiment, supervisor blade 602 classifies packet flows 610A-Bbased on one or more parameters contained in the packet headers of thosepacket flows. If the parameters contained in the packet header of aparticular packet match specified parameters, then supervisor blade 602sends the packets to a specified one of AONS blade 604 and/or otherblades 606A-N. Alternatively, if the parameters contained in the packetheader do not match any specified parameters, then supervisor blade 602performs routing functions relative to the particular packet andforwards the particular packet on toward the particular packet'sdestination.

For example, supervisor blade 602 may determine that packet headers inpacket flow 610B match specified parameters. Consequently, supervisorblade 602 may send packets in packet flow 610B to AONS blade 604.Supervisor blade 602 may receive packets back from AONS blade 604 and/orother blades 606A-N and send the packets on to the next hop in a networkpath that leads to those packets' destination. For another example,supervisor blade 602 may determine that packet headers in packet flow610A do not match any specified parameters. Consequently, withoutsending any packets in packet flow 610A to AONS blade 604 or otherblades 606A-N, supervisor blade 602 may send packets in packet flow 610Aon to the next hop in a network path that leads to those packets'destination.

AONS blade 604 and other blades 606A-N receive packets from supervisorblade 602, perform operations relative to the packets, and return thepackets to supervisor blade 602. Supervisor blade 602 may send packetsto and receive packets from multiple blades before sending those packetsout of router 600. For example, supervisor blade 602 may send aparticular group of packets to other blade 606A. Other blade 606A mayperform firewall functions relative to the packets and send the packetsback to supervisor blade 602. Supervisor blade 602 may receive thepacket from other blade 606A and send the packets to AONS blade 604.AONS blade 604 may perform one or more message payload-based operationsrelative to the packets and send the packets back to supervisor blade602.

According to one embodiment, the following events occur at an AONSrouter such as router 600. First, packets, containing messages fromclients to servers, are received. Next, access control list-basedfiltering is performed on the packets and some of the packets are sentto an AONS blade or module. Next, TCP termination is performed on thepackets. Next, Secure Sockets Layer (SSL) termination is performed onthe packets if necessary. Next, Universal Resource Locator (URL)-basedfiltering is performed on the packets. Next, message header-based andmessage content-based filtering is performed on the packets. Next, themessages contained in the packets are classified into AONS messagetypes. Next, a policy flow that corresponds to the AONS message type isselected. Next, the selected policy flow is executed. Then the packetsare either forwarded, redirected, dropped, copied, modified, orfanned-out as specified by the selected policy flow.

3.2 Performing Message Payload Processing Functions at a Network Element

FIGS. 3A-B depict a flow diagram 300 that illustrates one embodiment ofa method of performing message payload processing functions at a networkelement on behalf of an application. For example, one or more of networkelements 102, 104, 106, and 108 may perform such a method. Morespecifically, AONS blade 604 may perform one or more steps of such amethod. Other embodiments may omit one or more of the operationsdepicted in flow diagram 300. Other embodiments may contain operationsadditional to the operation depicted in flow diagram 300. Otherembodiments may perform the operations depicted in flow diagram 300 inan order that differs from the order depicted in flow diagram 300.

Referring first to FIG. 3A, in block 302, user-specified input isreceived at a network element. The user-specified input indicates thefollowing: one or more criteria that are to be associated with aparticular message classification, and one or more actions that are tobe associated with the particular message classification. Theuser-specified input may indicate an order in which the one or moreactions are to be performed. The user-specified input may indicate thatoutputs of actions are to be supplied as inputs to other actions. Forexample, network element 104, and more specifically AONS blade 604, mayreceive such user-specified input from a network administrator.

The user-specified input may indicate multiple sets of criteria that areto be associated, respectively, with multiple separate messageclassifications, and multiple sets of actions that are to be associatedwith the multiple message classifications. For example, theuser-specified input may indicate a first set of criteria that is to beassociated with a first message classification, a second set of criteriathat is to be associated with a second message classification, a firstset of actions that are to be associated with the first messageclassification, and a second set of actions that are to be associatedwith the second message classification.

In block 304, an association is established, at the network element,between the particular message classification and the one or morecriteria. For example, AONS blade 604 may establish an associationbetween a particular message classification and one or more criteria.For example, the criteria may indicate a particular string of text thata message needs to contain in order for the message to belong to theassociated message classification. For another example, the criteria mayindicate a particular path that needs to exist in the hierarchicalstructure of an XML-formatted message (or based in an XPath booleanexpression) in order for the message to belong to the associated messageclassification. For another example, the criteria may indicate one ormore source IP addresses and/or destination IP addresses from or towhich a message needs to be addressed in order for the message to belongto the associated message classification.

Multiple associations may be established between separate sets ofcriteria and separate message classifications. For example, AONS blade604 may establish a first association between a first set of criteriaand a first message classification, and a second association between asecond set of criteria and a second message classification.

In block 306, an association is established, at the network element,between the particular message classification and the one or moreactions. One or more actions that are associated with a particularmessage classification comprise a “policy” that is associated with thatparticular message classification. A policy may comprise a “flow” of oneor more actions that are ordered according to a particular orderspecified in the user-specified input, and/or one or more other actionsthat are not ordered. For example, AONS blade 604 may establish anassociation between a particular message classification and one or moreactions. Collectively, the operations of blocks 302-306 comprise“provisioning” the network element.

Multiple associations may be established between separate sets ofactions and separate message classifications. For example, AONS blade604 may establish a first association between a first set of actions anda first message classification, and a second association between asecond set of actions and a second message classification.

In block 308, one or more data packets that are destined for a deviceother than the network element are received by the network element. Thedata packets may be, for example, data packets that contain IP and TCPheaders. The IP addresses indicated in the IP headers of the datapackets may differ from the network element's IP address; thus, the datapackets may be destined for a device other than the network element. Forexample, network element 104, and more specifically supervisor blade602, may intercept data packets that client application 110 originallysent. The data packets might be destined for server application 112, forexample.

In block 310, based on one or more information items indicated in theheaders of the data packets, an application layer protocol that was usedto transmit a message contained in the payload portions of the datapackets (hereinafter “the message”) is determined. The information itemsmay include, for example, a source IP address in an IP header, adestination IP address in an IP header, a TCP source port in a TCPheader, and a TCP destination port in a TCP header. For example, networkelement 104, and more specifically AONS blade 604, may store mappinginformation that maps FTP (an application layer protocol) to a firstcombination of IP addresses and/or TCP ports, and that maps HTTP(another application layer protocol) to a second combination of IPaddresses and/or TCP ports. Based on this mapping information and the IPaddresses and/or TCP ports indicated by the data packets, networkelement 104 may determine which application layer protocol (FTP, HTTP,Simple Mail Transfer Protocol (SMTP), etc.) was used to transmit themessage.

In block 312, a message termination technique that is associated withthe application layer protocol used to transmit the message isdetermined. For example, network element 104, and more specifically AONSblade 604, may store mapping information that maps FTP to a firstprocedure, that maps HTTP to a second procedure, and that maps SMTP to athird procedure. The first procedure may employ a first messagetermination technique that can be used to extract, from the datapackets, a message that was transmitted using FTP. The second proceduremay employ a second message termination technique that can be used toextract, from the data packets, a message that was transmitted usingHTTP. The third procedure may employ a third message terminationtechnique that can be used to extract, from the data packets, a messagethat was transmitted using SMTP. Based on this mapping information andthe application layer protocol used to transmit the message, networkelement 104 may determine which procedure should be called to extractthe message from the data packets.

In block 314, the contents of the message are determined based on thetermination technique that is associated with the application layerprotocol that was used to transmit the message. For example, networkelement 104, and more specifically AONS blade 604, may provide the datapackets as input to a procedure that is mapped to the application layerprotocol determined in block 312. The procedure may use the appropriatemessage termination technique to extract the contents of the messagefrom the data packets. The procedure may return the message as output toAONS blade 604. Thus, in one embodiment, the message extracted from thedata packets is independent of the application layer protocol that wasused to transmit the message.

In one embodiment, determining the contents of the message involvesassembling the contents of the payload portions of two or more of thedata packets. For example, network element 104 may determine the properorder of two or more TCP data packets (based on TCP sequence numbers,for example), extract the contents of the payload portions of the TCPdata packets, and concatenate the contents according to the proper orderto form at least a portion of the message. The message may be amulti-part (MIME) message, and each part may be handled separately asthough it were a separate message; each part may be associated with adifferent message classification.

In block 316, a message classification that is associated with criteriathat the message satisfies is determined. For example, network element104 may store mapping information that maps different criteria todifferent message classifications. The mapping information indicates,among possibly many different associations, the association establishedin block 304. Network element 104 may determine whether the contents ofthe message satisfy criteria associated with any of the known messageclassifications. In one embodiment, if the contents of the messagesatisfy the criteria associated with a particular messageclassification, then it is determined that the message belongs to theparticular message classification.

Although, in one embodiment, the contents of the message are used todetermine a message's classification, in alternative embodiments,information beyond that contained in the message may be used todetermine the message's classification. For example, in one embodiment,a combination of the contents of the message and one or more IPaddresses and/or TCP ports indicated in the data packets that containthe message is used to determine the message's classification. Foranother example, in one embodiment, one or more IP addresses and/or TCPports indicated in the data packets that contain the message are used todetermine the message's classification, regardless of the contents ofthe message.

In block 318, one or more actions that are associated with the messageclassification determined in block 316 are performed. If two or more ofthe actions are associated with a specified order of performance, asindicated by the user-specified input, then those actions are performedin the specified order. If the output of any of the actions is supposedto be provided as input to any of the actions, as indicated by theuser-specified input, then the output of the specified action isprovided as input to the other specified action.

A variety of different actions may be performed relative to the message.For example, an action might indicate that the message is to be dropped.In this case, the message is prevented from being forwarded out of thenetwork element toward that message's destination. For another example,an action might indicate that a message is to be compressed using aspecified compression technique before being forwarded out of thenetwork element.

For another example, an action might indicate that the content of themessage is to be altered in a specified manner. For example, an actionmight indicate that specified text is to be inserted into a specifiedlocation in the message. A path in an XML hierarchical structure of themessage might specify such a location, for example, or a specifiedstring of text occurring in the message might specify such a location.For another example, an action might indicate that specified text is tobe deleted from the message. For another example, an action mightindicate that specified text is to be substituted for other specifiedtext in the message. Text inserted into the message might be obtaineddynamically (“on the fly”) from a database that is external to thenetwork element.

For another example, an action might indicate that the message format ofa message is to be altered in a specified manner. For example, an actionmight indicate that a message's format is to be changed from XML to someother format such as EDI. For another example, an action might indicatethat a message's format is to be changed from some format other than XMLinto XML. The message format may be altered without altering the corecontent of the message, which is independent of the message format.

For another example, an action might indicate that the message is to beforwarded using a specified application layer protocol other than theapplication layer protocol that the message's origin used to transmitthe message. For example, client application 110 might have used a firstapplication layer protocol, such as HTTP, to transmit the message. Thus,when intercepted by network element 104, and more specificallysupervisor blade 602, the message might have contained an HTTP header.However, in accordance with a specified action, before network element104 forwards the message towards the message's destination, networkelement 104, and more specifically AONS blade 604, may modify themessage so that the message will be carried using an application layerprotocol other than HTTP (such as FTP, SMTP, etc.).

For another example, an action might indicate that the message'sdestination is to be altered so that the message will be forwardedtowards a device that is different from the device that the message'ssource originally specified. For example, in accordance with a specifiedaction, network element 104, and more specifically AONS blade 604, mightencapsulate the message in one or more new IP data packets that indicatea new destination IP address that differs from the destination IPaddress that originally intercepted IP data packets indicated. Networkelement 104 may then forward the new IP data packets toward the newdestination. In this manner, message content-based routing may beachieved.

For another example, an action might indicate that a specified event isto be written into a specified log that might be external to the networkelement. For example, in accordance with a specified action, networkelement 104, and more specifically AONS blade 604, might write at leasta portion of the message, along with the IP address from which themessage was received, to a log file.

For another example, an action might indicate that the message is to beencrypted using a specified key before being forwarded to a destination.For example, in accordance with a specified action, network element 104,and more specifically AONS blade 604, might encrypt at least a portionof the message using a specified key and then forward data packets thatcontain the encrypted message towards the message's destination.Encryption also places a constraint on the subsequent action (e.g. Theencrypted portion cannot be modified).

For another example, an action might indicate that a response cached atthe network element is to be returned to the device from which themessage originated, if such a response is cached at the network element.For example, network element 104, and more specifically AONS blade 604,may determine whether a response to the message is cached at networkelement 104; such a response might have be cached at network element 104at the time a previous response to the same message passed throughnetwork element 104. If network element 104 determines that such aresponse is cached, then network element 104 may return the response tothe message's origin. For read-only operations without any persistentstate change, network element 104 does not need to forward the messageto the message's destination, and the message's destination does notneed to issue another response to the message.

For another example, an action might indicate that some authenticationinformation in the message, such as a user identifier and associatedpassword, is to be used to authenticate the message. For example,network element 104, and more specifically AONS blade 604, mightauthenticate a message by comparing authentication information in themessage with trusted information stored at network element 104.

If the message was modified in some way (e.g., content, format, orprotocol modification) during the performance of the actions, and if themodified message is supposed to be forwarded out of the network element,then the network element encapsulates the modified message into new datapackets and sends the new data packets towards the modified message'sdestination—which also might have been modified.

A message might not belong to any known message classification. In thiscase, according to one embodiment, the network element does not performany user-specified actions relative to the message. Instead, the networkelement simply forwards the data packets to the next hop along the pathto the data packets' indicated destination.

The method illustrated in flow diagram 300 may be performed relative tomultiple sets of data packets, each set carrying a separate message. Forexample, network element 104 may perform the method illustrated relativeto a first set of data packets that carry a first message, and thennetwork element 104 may perform the method relative to a second set ofdata packets that carry a second message. The first message mightsatisfy a first set of criteria associated with a first messageclassification, and the second message might satisfy a second set ofcriteria associated with a second message classification. Thus, networkelement 104 might perform a first set of actions relative to the firstmessage, and a second set of actions relative to the second message.

As a result of the method illustrated in flow diagram 300, applicationssuch as client application 110, server application 112, and serverapplication 114 can communicate with each other as though no networkelements acted as intermediaries, and as though each other applicationcommunicated using the same message format and application layerprotocol.

3.3 Action Flows

FIG. 4 depicts a sample flow 400 that might be associated with aparticular message classification. Flow 400 comprises, in order, actions402-414; other flows may comprise one or more other actions. Action 402indicates that the content of the message should be modified in aspecified manner. Action 404 indicates that a specified event should bewritten to a specified log. Action 406 indicates that the message'sdestination should be changed to a specified destination. Action 408indicates that the message's format should be translated into aspecified message format. Action 410 indicates that the applicationlayer protocol used to transmit the message or content should be changedto a specified application layer protocol. Action 412 indicates that themessage or content should be encrypted using a particular key. Action414 indicates that the message should be forwarded towards the message'sdestination. Other actions might include signing and verificationactions, for example.

In other embodiments, any one of actions 402-414 may be performedindividually or in combination with any others of actions 402-414.

3.4 Filtered Processing

Typically, inspecting, parsing, and modifying an application layermessage is a processing resource-intensive operation that cannot beperformed as quickly as routing operations that are based only oninformation in TCP and IP packet headers. Referring again to FIG. 6A,using packet level processing rather than message level processing,supervisor blade 602 might be able to process and send packets to AONSblade 604 faster than AONS blade 604 can process application layermessages contained within those packets. Indeed, there might be somepackets that contain application layer messages that AONS blade 604 doesnot need to process at all. Sending such packets to AONS blade 604 wouldonly waste processing resources and cause packet buffers of AONS blade604 to become backed up with packets.

Therefore, in one embodiment, supervisor blade 602 sends only someselected packets to AONS blade 604. The technique by which supervisorblade 602 selects these packets may be referred to as “filtering.” As aresult of filtering, AONS blade 604 does not receive as many packetswith which AONS blade 604 is likely to do nothing.

FIG. 6B depicts a flow diagram 650 that illustrates one embodiment of amethod of filtering packets for which message level processing is to beperformed. In block 652, it is determined whether information containedin a layer 2-4 header of a packet or frame satisfies specified criteria.The criteria might specify particular sources and/or particulardestinations that packets need to be coming from and/or going to inorder to merit message level processing. For example, supervisor blade602 might determine whether a combination of one or more of a packet'ssource IP address, source TCP port, destination IP address, anddestination TCP port match any user-specified combinations of theseaddresses and ports. If the header information satisfies the specifiedcriteria, then control passes to block 654. Otherwise, control passes toblock 656.

In block 654, the packet is sent to an AONS blade. For example,supervisor blade 602 may direct the packet to AONS blade 604. AONS blade604 may then perform more resource-intensive message level processing onan application layer message that is at least partially contained in thepacket.

Alternatively, in block 656, the packet is forwarded on towards thepacket's destination. For example, supervisor blade 602 may route thepacket toward the packet's next hop without sending the packet to AONSblade 604. Message level processing is not performed on the packet.

3.5 AONS Examples

-   -   3.5.1 AONS General Overview

Application-Oriented Network Systems (AONS) is a technology foundationfor building a class of products that embed intelligence into thenetwork to better meet the needs of application deployment. AONScomplements existing networking technologies by providing a greaterdegree of awareness of what information is flowing within the networkand helping customers to integrate disparate applications by routinginformation to the appropriate destination, in the format expected bythat destination; enforce policies for information access and exchange;optimize the flow of application traffic, both in terms of networkbandwidth and processing overheads; provide increased manageability ofinformation flow, including monitoring and metering of information flowfor both business and infrastructure purposes; and provide enhancedbusiness continuity by transparently backing up or re-routing criticalbusiness data.

AONS provides this enhanced support by understanding more about thecontent and context of information flow. As such, AONS works primarilyat the message rather than at the packet level. Typically, AONSprocessing of information terminates a TCP connection to inspect thefull message, including the “payload” as well as all headers. AONS alsounderstands and assists with popular application-level protocols such asHTTP, FTP, SMTP and de facto standard middleware protocols.

AONS differs from middleware products running on general-purposecomputing systems in that AONS' behavior is more akin to a networkappliance, in its simplicity, total cost of ownership and performance.Furthermore, AONS integrates with network-layer support to provide amore holistic approach to information flow and management, mappingrequired features at the application layer into low-level networkingfeatures implemented by routers, switches, firewalls and othernetworking systems.

Although some elements of AONS-like functionality are provided inexisting product lines from Cisco Systems, Inc., such products typicallywork off a more limited awareness of information, such as IP/portaddresses or HTTP headers, to provide load balancing and failoversolutions. AONS provides a framework for broader functional support, abroader class of applications and a greater degree of control andmanagement of application data.

-   -   3.5.2 AONS Terminology

An “application” is a software entity that performs a business functioneither running on servers or desktop systems. The application could be apackaged application, software running on application servers, a legacyapplication running on a mainframe, or custom or proprietary softwaredeveloped in house to satisfy a business need or a script that performssome operation. These applications can communicate with otherapplications in the same department (departmental), across departmentswithin a single enterprise (intra enterprise), across an enterprise andits partners (inter-enterprise or B2B) or an enterprise and itscustomers (consumers or B2C). AONS provides value added services for anyof the above scenarios.

An “application message” is a message that is generated by anapplication to communicate with another application. The applicationmessage could specify the different business level steps that should beperformed in handling this message and could be in any of the messageformats described in the section below. In the rest of the document,unless otherwise specified explicitly, the term “message” also refers toan application message.

An “AONS node” is the primary AONS component within the AONS system (ornetwork). As described later, the AONS node can take the shape of aclient proxy, server proxy or an intermediate device that routesapplication messages.

Each application message, when received by the first AONS node, getsassigned an AONS message ID and is considered to be an “AONS message”until that message gets delivered to the destination AONS node. Theconcept of the AONS message exists within the AONS cloud. A singleapplication message may map to more than one AONS message. This may bethe case, for example, if the application message requires processing bymore than one business function. For example, a “LoanRequest” messagethat is submitted by a requesting application and that needs to beprocessed by both a “CreditCheck” application and a “LoanProcessing”application would require processing by more than one business function.In this example, from the perspective of AONS, there are two AONSmessages: The “LoanRequest” to the “CreditCheck” AONS message from therequesting application to the CreditCheck application; and the“LoanRequest” to the “LoanProcessing” AONS message from the CreditCheckapplication to the LoanProcessing Application.

In one embodiment, AONS messages are encapsulated in an AONP (AONProtocol) message that contains AONP headers, and are translated to a“canonical” format. AONP is a mechanism to enable federation between twoor more AONS nodes. For example, a first AONS node may know that it isacting in conjunction with a second or other AONS node; thus the AONSnodes are “federated.” The first AONS node might have performed one ormore actions, such as encryption, signing, authentication, etc.,relative to a particular message. The first AONS node may indicate, inone or more AONP headers, the actions that the first AONS nodeperformed. Upon receiving the AONP message, the second AONS node maydetermine from the AONP headers that the actions have been performed. Asa result, the second AONS node may forego performing those actions, orperform other functions in an efficient and optimal way. Reliability,logging and security services are provided from an AONS messageperspective.

The set of protocols or methods that applications typically use tocommunicate with each other are called “application access protocols”(or methods) from an AONS perspective. Applications can communicate tothe AONS network (typically end point proxies: a client proxy and aserver proxy) using any supported application access methods. Someexamples of application access protocols include: IBM MQ Series, JavaMessage Service (JMS), TIBCO, Simple Object Access Protocol (SOAP) overHypertext Transfer Protocol (HTTP)/HTTPS, Simple Mail Transfer Protocol(SMTP), File Transfer Protocol (FTP), Java Database Connectivity (JDBC),TCP, etc. Details about various access methods are explained in latersections of this document.

There are a wide variety of “message formats” that are used byapplications. These message formats may range from custom or proprietaryformats to industry-specific formats to standardized formats. ExtensibleMarkup Language (XML) is gaining popularity as a universal language ormessage format for applications to communicate with each other. AONSsupports a wide variety of these formats.

In addition, in one embodiment, AONS provides content translationservices from one format to another based on the needs of applications.A typical deployment might involve a first AONS node that receives anapplication message (the client proxy) translating the message to a“canonical” format, which is carried as an AONS message through the AONSnetwork. The server proxy might translate the message from the“canonical” format to the format understood by the receiving applicationbefore delivering the message. However, proxies are not required. Forunderstanding some of the non-industry standard formats, a messagedictionary may be used.

A node that performs the gateway functionality between multipleapplication access methods or protocols is called a “protocol gateway.”An example of this would be a node that receives an application messagethrough File Transfer Protocol (FTP) and sends the same message toanother application as a HTTP post. In AONS, the client and serverproxies are typically expected to perform the protocol gatewayfunctionality.

If an application generates a message in Electronic Data Interchange(EDI) format and if the receiving application expects the message to bein an XML format, then the message format needs to be translated but thecontent of the message needs to be kept intact through the translation.In AONS, the end point proxies typically perform this “message formattranslation” functionality.

In some cases, even though the sending and receiving application use thesame message format, the content needs to be translated for thereceiving application. For example, if a United States-residentapplication is communicating with a United Kingdom-resident application,then the date format in the messages between the two applications mightneed to be translated (from mm/dd/yyyy to dd/mm/yyyy) even if theapplications use the same data representation (or message format). Thistranslation is called “content translation.”

-   -   3.5.3 AONS Functional Overview

As defined previously, AONS can be defined as network-based intelligentintermediary systems that efficiently and effectively integrate businessand application needs with more flexible and responsive networkservices.

In particular, AONS can be understood through the followingcharacteristics:

AONS operates at a higher layer (layers 5-6) than traditional networkelement products (layers 2-4). AONS uses message-level inspection as acomplement to packet-level inspection—by understanding applicationmessages, AONS adds value to multiple network element products, such asswitches, firewalls, content caching systems and load balancers, on the“message exchange route.” AONS provides increased flexibility andgranularity of network responsiveness in terms of security, reliability,traffic optimization (compression, caching), visibility (business eventsand network events) and transformation (e.g., from XML to EDI).

AONS is a comprehensive technology platform, not just a point solution.AONS can be implemented through distributed intelligent intermediarysystems that sit between applications, middleware, and databases in adistributed intra- and inter-enterprise environment (routing messages,performing transformations, etc.). AONS provides a flexible frameworkfor end user configuration of business flows and policies andpartner-driven extensibility of AONS services.

AONS is especially well suited for network-based deployment. AONS isnetwork-based rather than general-purpose server-based. AONS is hybridsoftware-based and hardware-based (i.e., application-specific integratedcircuit (ASIC)/field programmable gate array (FPGA)-based acceleration).AONS uses out-of-band or in-line processing of traffic, as determined bypolicy. AONS is deployed in standalone products (network appliances) aswell as embedded products (service blades for multiple switching,routing, and storage platforms).

-   -   3.5.4 AONS System Overview

This section outlines the system overview of an example AONS system.FIG. 7 is a diagram 700 that illustrates the various components involvedin an example AONS network 702 according to one embodiment of theinvention. The roles performed by each of the nodes are mentioned indetail in subsequent sections.

Within AONS network 702, key building blocks include AONS EndpointProxies (AEPs) 704-710, which are located at the edge of the AONSnetwork and serve as the entry and exit points, and an AONS Router (AR),which is located within the AONS network. Visibility into applicationintent may begin within AEP 704 placed at the edge of a logical AONS“cloud.” As a particular client application of client applications714A-N attempts to send a message across the network to a particularserver application destination of server applications 716A-N and 718A-N,the particular client application will first interact with AEP 704.

AEP 704 serves as either a transparent or explicit messaging gatewaywhich aggregates network packets into application messages and infersthe message-level intent by examining the header and payload of a givenmessage, relating the message to the appropriate context, optionallyapplying appropriate policies (e.g. message encryption, transformation,etc.) and then routing the message towards the message's applicationdestination via a network switch.

AONS Router (AR) 712 may intercept the message en route to the message'sdestination endpoint. Based upon message header contents, AR 712 maydetermine that a new route would better serve the needs of a givenapplication system. AR 712 may make this determination based uponenterprise-level policy, taking into account current network conditions.As the message nears its destination, the message may encounter AEP 706,which may perform a final set of operations (e.g. message decryption,acknowledgement of delivery) prior to the message's arrival. In oneembodiment, each message is only parsed once: when the message firstenters the AONS cloud. It is the first AEP that a message traverses thatis responsible for preparing a message for optimal handling within theunderlying network.

AEPs 704-708 can further be classified into AEP Client Proxies and AEPServer Proxies to explicitly highlight roles and operations performed bythe AEP on behalf of the specific end point applications.

A typical message flow involves a particular client application 714Asubmitting a message to the AEP Client Proxy (CP) 704 through one of thevarious access protocols supported by AONS. On receiving this message,AEP CP 704 assigns an AONS message id to the message, encapsulates themessage with an AONP header, and performs any necessary operationsrelated to the AONS network (e.g. security and reliability services).Also, if necessary, the message is converted to a “canonical” format byAEP CP 704. The message is carried over a TCP connection to AR 710 alongthe path to the destination application 718A. The AONS routers orswitches along the path perform the infrastructure services necessaryfor the message and can change the routing based on the policiesconfigured by the customer. The message is received at the destinationAEP Server Proxy (SP) 706. AEP SP 706 performs necessary security andreliability functions and translates the message to the format that isunderstood by the receiving application, if necessary. AEP SP 706 thensends the message to receiving application 718A using any of the accessprotocols that application 718A and AONS support. A detailed messageflow through AONS network 702 is described in later sections.

The message processing described herein may be performed with respect tothe content of different kinds of messages that an AONS node mayencounter. AONS nodes may process request messages, response messages,messages that called out from an AONS node or that are brought into anAONS node, or exception messages; AONS nodes may process contents ofmessages beyond those or the type that are sent between client andserver applications. For example, in response to intercepting a messagefrom a client application, an AONS node may generate and send anothermessage to a database server. The AONS may subsequently receive yetanother message from the database server. The AONS node may performmessage processing in the manner described herein on any of the messagesmentioned above, not just on the messages from the client.

An AONS node may perform specified actions in response to determiningthat the delivery of a message will cause a failure. For example, anAONS node may determine that a message is larger than the maximum sizethat can be accepted by a server application for which the message isdestined. In response, the AONS node may prevent the message from beingforwarded to the server application. Instead, the AONS node may log themessage for later inspection by an administrator. For another example,in response to determining that a message contains a virus or othermalignant content, an AONS node may “inoculate” the message (e.g., byencrypting and/or compressing the message content), and then store the“inoculated” message in a log for later inspection by an administrator.

-   -   3.5.5 AONS System Elements

This section outlines the different concepts that are used from an AONSperspective.

An “AEP Client Proxy” is an AONS node that performs the servicesnecessary for applications on the sending side of a message (a client).In the rest of this document, an endpoint proxy also refers to a clientor server proxy. Although AONS nodes may fulfill the roles of proxies,they are typically not designated as such; “AEP proxy” is a term used todefine a role. The typical responsibilities of the client proxy inprocessing a message are: message pre-classification & early rejection,protocol management, message identity management, message encapsulationin an AONP header, end point origination for reliable delivery, securityend point service origination (encryption, digital signature,authentication), flow selection & execution/infrastructure services(logging, compression, content transformation, etc.), routing—next hopAONS node or destination, AONS node and route discovery/advertising roleand routes, and end point origination for the reliable deliverymechanism (guaranteed delivery router).

Not all functionalities described above need to be performed for eachmessage. The functionalities performed on the message are controlled bythe policies configured for the AONS node.

An “AEP Server Proxy” is an AONS node that performs the servicesnecessary for applications on the receiving side of a message (aserver). In the rest of the document, a Server Proxy may also bereferred as an end point proxy. The typical responsibilities of theServer Proxy in processing a message are: protocol management, end pointtermination for reliable delivery, security end point servicetermination (decryption, verification of digital signature, etc.), flowselection & execution/infrastructure services (logging, compression,content translation, etc.), message de-encapsulation in AONP header,acknowledgement to sending AONS node, application routing/requestmessage delivery to destination, response message correlation, androuting to entry AONS node.

Note that not all the functionalities listed above need to be performedfor each message. The functionalities performed on the message arecontrolled by the policies configured for the AONS node and what themessage header indicates.

An “AONS Router” is an AONS node that provides message-forwardingfunctionalities along with additional infrastructure services within anAONS network. An AONS Router communicates with Client Proxies, ServerProxies and other AONS Routers. An AONS Router may provide servicewithout parsing a message; an AONS Router may rely on an AONP messageheader and the policies configured in the AONS network instead ofparsing messages. An AONS Router provides the following functionalities:scalability in the AONS network in terms of the number of TCPconnections needed; message routing based on message destination,policies configured in the AONS cloud, a route specified in the message,and/or content of the message; a load at the intendeddestination—re-routing if needed; availability of thedestination—re-routing if needed; cost of transmission (selection amongmultiple service providers); and infrastructure services such as sendingto a logging facility, sending to a storage area network (SAN) forbackup purposes, and interfacing to a cache engine for cacheablemessages (like catalogs).

AONS Routers do not need to understand any of the application accessprotocols and, in one embodiment, deal only with messages encapsulatedwith an AONP header.

Application-Oriented Networking Protocol (AONP) is a protocol used forcommunication between the nodes in an AONS network. In one embodiment,each AONS message carries an AONP header that conveys the destination ofthe message and additional information for processing the message insubsequent nodes. AONP also addresses policy exchange (static ordynamic), fail-over among nodes, load balancing among AONS nodes, andexchange of routing information. AONP also enables application-orientedmessage processing in multiple network elements (like firewalls, cacheengines and routers/switches). AONP supports both a fixed header and avariable header (formed using type-length-value (TLV) fields) to supportefficient processing in intermediate nodes as well as flexibility foradditional services.

Unless explicitly specified otherwise, “router” or “switch” refersherein to a typical Layer 3 or Layer 2 switch or a router that iscurrently commercially available.

-   -   3.5.6 AONS Example Features

In one embodiment, an underlying “AONS foundation platform of subsystemservices” (AOS) provides a range of general-purpose services includingsupport for security, compression, caching, reliability, policymanagement and other services. On top of this platform, AONS then offersa range of discreet functional components that can be wired together toprovide the overall processing of incoming data traffic. These“bladelets™” are targeted at effecting individual services in thecontext of the specific policy or action demanded by the application orthe information technology (IT) manager. A series of access methodadaptors ensure support for a range of ingress and egress formats.Finally, a set of user-oriented tools enable managers to appropriatelyview, configure and set policies for the AONS solution. These fourcategories of functions combine to provide a range of end-customercapabilities including enhanced security, infrastructure optimization,business continuity, application integration and operational visibility.

The enhanced visibility and enhanced responsiveness enabled by AONSsolutions provides a number of intelligent, application-oriented networkservices. These intelligent services can be summarized in four primarycategories:

Enhanced security and reliability: enabling reliable message deliveryand providing message-level security in addition to existingnetwork-level security.

Infrastructure optimization: making more efficient use of networkresources by taking advantage of caching and compression at the messagelevel as well as by integrating application and networkquality-of-service (QoS).

Business and infrastructure activity monitoring and management: byreading information contained in the application layer message, AONS canlog, audit, and manage application-level business events, and combinethese with network, server, and storage infrastructure events in acommon, policy-driven management environment.

Content-based routing and transformation: message-based routing andtransformation of protocol, content, data, and message formats (e.g.,XML transformation). The individual features belonging to each of theseprimary categories are described in greater detail below.

-   -   3.5.6.1 Enhanced Security and Reliability

Authentication: AONS can verify the identity of the sender of an inboundmessage based upon various pieces of information contained within agiven message (username/password, digital certificate, SecurityAssertion Markup Language (SAML) assertion, etc.), and, based upon thesecredentials, determine whether or not the message should be processedfurther.

Authorization: Once principal credentials are obtained via messageinspection, AONS can determine what level of access the originator ofthe message should have to the services it is attempting to invoke. AONSmay also make routing decisions based upon such derived privileges orblock or mask certain data elements within a message once it's within anAONS network as appropriate.

Encryption/Decryption: Based upon policy, AONS can perform encryption ofmessage elements (an entire message, the message body or individualelements such as credit card number) to maintain end-to-endconfidentiality as a message travels through the AONS network.Conversely, AONS can perform decryption of these elements prior toarrival at a given endpoint.

Digital Signatures: In order to ensure message integrity and allow fornon-repudiation of message transactions, AONS can digitally sign entiremessages or individual message elements at any given AEP. The decisionas to what gets signed will be determined by policy as applied toinformation derived from the contents and context of each message.

Reliability: AONS can complement existing guaranteed messaging systemsby intermediating between unlike proprietary mechanisms. It can alsoprovide reliability for HTTP-based applications (including web services)that currently lack reliable delivery. As an additional feature, AONScan generate confirmations of successful message delivery as well asautomatically generate exception responses when delivery cannot beconfirmed.

-   -   3.5.6.2 Infrastructure Optimization

Compression and stream-based data extraction: AEPs can compress messagedata prior to sending the message data across the network in order toconserve bandwidth and conversely decompress it prior to endpointdelivery. AEPs can also extract data to perform message classificationwithout waiting for the whole message to be read in.

Caching: AONS can cache the results of previous message inquires basedupon the rules defined for a type of request or based upon indicatorsset in the response. Caching can be performed for entire messages or forcertain elements of a message in order to reduce application responsetime and conserve network bandwidth utilization. Message element cachingenables delta processing for subsequent message requests.

TCP Connection Pooling: By serving as an intermediary between messageclients and servers AONS can consolidate the total number of persistentconnections required between applications. AONS thereby reduces theclient and server-processing load otherwise associated with the ongoinginitiation and teardown of connections between a mesh of endpoints.

Batching: An AONS intermediary can batch transactional messages destinedfor multiple destinations to reduce disk I/O overheads on the sendingsystem. Similarly, transactional messages from multiple sources can bebatched to reduce disk I/O overheads on the receiving system.

Hardware Acceleration: By efficiently performing compute-intensivefunctions such as encryption and Extensible Stylesheet LanguageTransformation (XSLT) transformations in an AONS network device usingspecialized hardware, AONS can offload the computing resources ofendpoint servers, providing potentially lower-cost processingcapability.

Quality of Service: AONS can integrate application-level QoS withnetwork-level QoS features based on either explicit messageprioritization (e.g., a message tagged as “high priority”) or via policythat determines when a higher quality of network service is required fora message as specific message content is detected.

Policy Enforcement: At the heart of optimizing the overall AONS solutionis the ability to ensure business-level polices are expressed,implemented and enforced by the infrastructure. The AONS Policy Managerensures that once messages are inspected, the appropriate actions(encryption, compression, routing, etc.) are taken against that messageas appropriate.

-   -   3.5.6.3 Activity Monitoring and Management

Auditing/Logging/Metering: AONS can selectively filter messages and sendthem to a node or console for aggregation and subsequent analysis. Toolsenable viewing and analysis of message traffic. AONS can also generateautomatic responses to significant real-time events, both business andinfrastructure-related. By intelligently gathering statistics andsending them to be logged, AONS can produce metering data for auditingor billing purposes.

Management: AONS can combine both message-level and networkinfrastructure level events to gain a deeper understanding of overallsystem health. The AONS management interface itself is available as aweb service for those who wish to access it programmatically.

Testing and Validation: AONS' ability to intercept message traffic canbe used to validate messages before allowing them to reach destinationapplications. In addition to protecting from possible application orserver failures, this capability can be leveraged to test new webservices and other functions by examining actual message flow fromclients and servers prior to production deployment. AONS also provides a“debug mode” that can be turned on automatically after a suspectedfailure or manually after a notification to assist with the overallmanagement of the device.

Workload Balancing and Failover: AONS provides an approach to workloadbalancing and failover that is both policy- and content-driven. Forexample, given an AONS node's capability to intermediate betweenheterogeneous systems, the AONS node can balance between unlike systemsthat provide access to common information as requested by the contentsof a message. AONS can also address the issue of message affinitynecessary to ensure failover at the message rather than just the sessionlevel as is done by most existing solutions. Balancing can also takeinto account the response time for getting a message reply, routing toan alternate destination if the preferred target is temporarily slow torespond.

Business Continuity: By providing the ability to replicate inboundmessages to a remote destination, AONS enables customers to quicklyrecover from system outages. AONS can also detect failed messagedelivery and automatically re-route to alternate endpoints. AONS AEPsand ARs themselves have built-in redundancy and failover at thecomponent level and can be clustered to ensure high availability.

-   -   3.5.6.4 Content-Based Routing and Transformation

Content-based Routing: Based upon its ability to inspect and understandthe content and context of a message, AONS provides the capability toroute messages to an appropriate destination by matching contentelements against pre-established policy configurations. This capabilityallows AONS to provide a common interface (service virtualization) formessages handled by different applications, with AONS examining messagetype or fields in the content (part number, account type, employeelocation, customer zip code, etc.) to route the message to theappropriate application. This capability also allows AONS to send amessage to multiple destinations (based on either statically defined ordynamic subscriptions to message types or information topics), withoptimal fan-out through AONS routers. This capability further allowsAONS to redirect all messages previously sent to an application so thatit can be processed by a new application. This capability additionallyallows AONS to route a message for a pre-processing step that is deemedto be required before receipt of a message (for example, introducing amanagement pre-approval step for all travel requests). This capabilityalso allows AONS to route a copy of a message that exceeds certaincriteria (e.g. value of order) to an auditing system, as well asforwarding the message to the intended destination. This capabilityfurther allows AONS to route a message to a particular server forworkload or failover reasons. This capability also allows AONS to routea message to a particular server based on previous routing decisions(e.g., routing a query request based on which server handled for theoriginal order). This capability additionally allows AONS to route basedon the source of a message. This capability also allows AONS to route amessage through a sequence of steps defined by a source or previousintermediary.

Message Protocol Gateway: AONS can act as a gateway between applicationsusing different transport protocols. AONS supports open standardprotocols (e.g. HTTP, FTP, SMTP), as well as popular or de factostandard proprietary protocols such as IBM MQ and JMS.

Message Transformations: AONS can transform the contents of a message tomake them appropriate for a particular receiving application. This canbe done for both XML and non-XML messages, the latter via the assistanceof either a message dictionary definition or a well-defined industrystandard format.

-   -   3.5.7 AONS Functional Modules

FIG. 8 is a block diagram that depicts functional modules within anexample AONS node. AONS node 800 comprises AOS configuration andmanagement module 802, flows/rules 804, AOS common services 806, AOSmessage execution controller 808, AOS protocol access methods 810, andAOS platform-specific “glue” 812. AONS node 800 interfaces withInternetworking Operating System (IOS) 814 and Linux Operating System816. Flows/rules 804 comprise bladelets™ 818, scriptlets™ 820, andscriptlet™ container 822.

In one embodiment, AOS common services 806 include: security services,standard compression services, delta compression services, cachingservice, message logging service, policy management service, reliablemessaging service, publish/subscribe service, activity monitoringservice, message distribution service, XML parsing service, XSLTtransformation service, and QoS management service.

In one embodiment, AOS protocol/access methods 810 include: TCP/SSL,HTTP/HTTPS, SOAP/HTTP, SMTP, FTP, JMS/MQ and JMS/RV, and Java DatabaseConnectivity (JDBC).

In one embodiment, AOS message execution controller 808 includes: anexecution controller, a flow subsystem, and a bladelet™ subsystem.

In one embodiment, AOS bladelets™ 818 and scriptlets™ 820 include:message input (read message), message output (send message),logging/audit, decision, external data access, XML parsing, XMLtransformation, caching, scriptlet container, publish, subscribe,message validation (schema, format, etc.), filtering/masking, signing,authentication, authorization, encryption, decryption, activitymonitoring sourcing, activity monitoring marking, activity monitoringprocessing, activity monitoring notification, message discard, firewallblock, firewall unblock, message intercept, and message stop-intercept.

In one embodiment, AOS configuration and management module 802 includes:configuration, monitoring, topology management, capability exchange,failover redundancy, reliability/availability/serviceability (RAS)services (tracing, debugging, etc.), archiving, installation, upgrades,licensing, sample scriptlets™, sample flows, documentation, online help,and language localization.

In one embodiment, supported platforms include: Cisco Catalyst 6503,Cisco Catalyst 6505, Cisco Catalyst 6509, and Cisco Catalyst 6513. Theseproducts are typically deployed in data centers. Other products, such as“branch office routers” (e.g., the Cisco Volant router series) and “edgerouters” are also supported. In one embodiment, supported supervisormodules include: Sup2 and Sup720. In one embodiment, specific functionalareas relating to the platform include: optimized TCP, SSL, public keyinfrastructure (PKI), encryption/decryption, interface to Cat6Ksupervisor, failover/redundancy, image management, and QoSfunctionality. Although some embodiments of the invention are describedherein with reference to PKI keys, embodiments of the invention are notlimited to PKI keys. Other keys and/or tokens, such as Kerberos tokensand/or PGP tokens, may be used in conjunction with embodiments of theinvention.

In one embodiment, cryptographic key distribution and processing iscontrolled by user-specified policies that are stored, with the keys, ata central console called an AMC. The policies may state, for example,that different kinds of keys are to be used to encrypt/decrypt/signdifferent kinds of data traffic. Keys may be associated with policies.The AMC may automatically distribute the key-to-policy associations touser-specified AONS nodes.

-   -   3.5.8 AONS Modes of Operation

AONS may be configured to run in multiple modes depending on applicationintegration needs, and deployment scenarios. According to oneembodiment, the primary modes of operation include implicit mode,explicit mode, and proxy mode. In implicit mode, an AONS nodetransparently intercepts relevant traffic with no changes toapplications. In explicit mode, applications explicitly address trafficto an intermediary AONS node. In proxy mode, applications are configuredto work in conjunction with AONS nodes, but applications do notexplicitly address traffic to AONS nodes.

In implicit mode, applications are unaware of AONS presence. Messagesare addressed to receiving applications. Messages are redirected to AONSvia configuration of application “proxy” or middleware systems to routemessages to AONS, and/or via configuration of networks (packetinterception). For example, domain name server (DNS)-based redirectioncould be used to route messages. For another example, a 5-tuple-basedaccess control list (ACL) on a switch or router could be used.Network-based application recognition and content switching modules maybe configured for URL/URI redirection. Message-based inspection may beused to determine message types and classifications. In implicit mode,applications communicate with each other using AONS as an intermediary(implicitly), using application-native protocols.

Traffic redirection, message classification, and “early rejection”(sending traffic out of AONS layers prior to complete processing withinAONS layers) may be accomplished via a variety of mechanisms, such asthose depicted in FIG. 9. FIG. 9 shows multiple tiers of filtering thatmay be performed on message traffic in order to produce only a selectset of traffic that will be processed at the AONS layer. Traffic that isnot processed at the AONS layer may be treated as any other traffic.

At the lowest layer, layer 902, all traffic passes through. At the nexthighest layer, layer 904, traffic may be filtered based on 5-tuples. Asupervisor blade or a network operating system such as InternetworkOperating System (IOS) may perform such filtering. Traffic that passesthe filters at layer 904 passes to layer 906. At layer 906, traffic maybe further filtered based on network-based application recognition-likefiltering and/or message classification and rejection. Traffic thatpasses the filters at layer 906 passes to layer 908. At layer 908,traffic may be further filtered based on protocol headers. For example,traffic may be filtered based on URLs/URIs in the traffic. Traffic thatpasses the filters at layer 908 passes to layer 910. At layer 910,traffic may be processed based on application layer messages, includeheaders and contents. For example, XPath content identificationtechnology within messages may be used to process traffic at layer 910.An AONS blade may perform processing at layer 910. Thus, a select subsetof all network traffic may be provided to an AONS blade.

In explicit mode, applications are aware of AONS presence. Messages areexplicitly addressed to AONS nodes. Applications may communicate withAONS using AONP. AONS may perform service virtualization and destinationselection.

In proxy mode, applications are explicitly unaware of AONS presence.Messages are addressed to their ultimate destinations (i.e.,applications). However, client applications are configured to directtraffic via a proxy mode.

-   -   3.5.9 AONS Message Routing

Components of message management in AONS may be viewed from twoperspectives: a node view and a cloud view.

FIG. 10 is a diagram that illustrates the path of a message within anAONS cloud 1010 according to a cloud view. A client application 1004sends a message to an AONS Client Proxy (CP) 1006. If AONS CP 1006 isnot present, then client application 1004 may send the message to anAONS Server Proxy (SP) 1008. The message is processed at AONS CP 1006.AONS CP 1006 transforms the message into AONP format if the message isentering AONS cloud 1010.

Within AONS cloud 1010, the message is routed using AONP. Thus, usingAONP, the message may be routed from AONS CP 1006 to an AONS router1012, or from AONS CP 1006 to AONS SP 1008, or from AONS router 1012 toanother AONS router, or from AONS router 1012 to AONS SP 1008. Messagesprocessed at AONS nodes are processed in AONP format.

When the message reaches AONS SP 1008, AONS SP 1008 transforms themessage into the message format used by server application 1014. AONS SP1008 routes the message to server application 1014 using the messageprotocol of server application 1014. Alternatively, if AONS SP 1008 isnot present, AONS CP 1006 may route the message to server application1014.

The details of the message processing within AONS cloud 1010 can beunderstood via the following perspectives: Request/Response MessageFlow, One-Way Message Flow, Message Flow with Reliable Delivery,Node-to-Node Communication, and multicast publish-subscribe.

FIG. 11A and FIG. 11B are diagrams that illustrate a request/responsemessage flow. Referring to FIG. 11A, at circumscribed numeral 1, asending application 1102 sends a message towards a receiving application1104. At circumscribed numeral 2, an AEP CP 1106 intercepts the messageand adds an AONP header to the message, forming an AONP message. Atcircumscribed numeral 3, AEP CP 1106 sends the AONP message to an AONSrouter 1108. At circumscribed numeral 4, AONS router 1108 receives theAONP message. At circumscribed numeral 5, AONS router 1108 sends theAONP message to an AEP SP 1110. At circumscribed numeral 6, AEP SP 1110receives the AONP message and removes the AONP header from the message,thus decapsulating the message. At circumscribed numeral 7, AEP SP 1110sends the message to receiving application 1104.

Referring to FIG. 11B, at circumscribed numeral 8, receiving application1104 sends a response message toward sending application 1102. Atcircumscribed numeral 9, AEP SP 1110 intercepts the message and adds anAONP header to the message, forming an AONP message. At circumscribednumeral 10, AEP SP 1110 sends the AONP message to AONS router 1108. Atcircumscribed numeral 11, AONS router 1108 receives the AONP message. Atcircumscribed numeral 12, AONS router 1108 sends the AONP message to AEPCP 1106. At circumscribed numeral 13, AEP CP 1106 receives the AONPmessage and removes the AONP header from the message, thus decapsulatingthe message. At circumscribed numeral 14, AEP CP 1106 sends the messageto sending application 1102. Thus, a request is routed from sendingapplication 1102 to receiving application 1104, and a response is routedfrom receiving application 1104 to sending application 1102.

FIG. 12A and FIG. 12B are diagrams that illustrate alternativerequest/response message flows. FIG. 12A shows three possible routesthat a message might take from a sending application 1202 to a receivingapplication 1204. According to a first route, sending application 1202sends the message toward receiving application 1204, but an AEP CP 1206intercepts the message and sends the message to receiving application1204. According to a second route, sending application 1202 sends themessage toward receiving application 1204, but AEP CP 1206 interceptsthe message, encapsulates the message within an AONP message, and sendsthe AONP message to an AEP SP 1208, which decapsulates the message fromthe AONP message and sends the message to receiving application 1204.According to a third route, sending application 1202 sends the messagetoward receiving application 1204, but AEP SP 1208 intercepts themessage and sends the message to receiving application 1204.

FIG. 12B shows three possible routes that a response message might takefrom receiving application 1204 to sending application 1202. Accordingto a first route, receiving application 1204 sends the message towardsending application 1202, but AEP CP 1206 intercepts the message andsends the message to sending application 1204. According to a secondroute, receiving application 1204 sends the message toward sendingapplication 1202, but AEP SP 1208 intercepts the message, encapsulatesthe message within an AONP message, and sends the AONP message to AEP CP1206, which decapsulates the message from the AONP message and sends themessage to sending application 1202. According to a third route,receiving application 1204 sends the message toward sending application1202, but AEP SP 1208 intercepts the message and sends the message tosending application 1202.

FIG. 13 is a diagram that illustrates a one-way message flow. Atcircumscribed numeral 1, a sending application 1302 sends a messagetowards a receiving application 1304. At circumscribed numeral 2, an AEPCP 1306 intercepts the message and adds an AONP header to the message,forming an AONP message. At circumscribed numeral 3, AEP CP 1306 sendsan ACK (acknowledgement) back to sending application 1302. Atcircumscribed numeral 4, AEP CP 1306 sends the AONP message to an AONSrouter 1308. At circumscribed numeral 5, AONS router 1308 receives theAONP message. At circumscribed numeral 6, AONS router 1308 sends theAONP message to an AEP SP 1310. At circumscribed numeral 7, AEP SP 1310receives the AONP message and removes the AONP header from the message,thus decapsulating the message. At circumscribed numeral 8, AEP SP 1310sends the message to receiving application 1304.

FIG. 14 is a diagram that illustrates alternative one-way message flows.FIG. 14 shows three possible routes that a message might take from asending application 1402 to a receiving application 1404. According to afirst route, sending application 1402 sends the message toward receivingapplication 1404, but an AEP CP 1406 intercepts the message and sendsthe message to receiving application 1404. AEP CP 1406 sends an ACK(acknowledgement) to sending application 1402. According to a secondroute, sending application 1402 sends the message toward receivingapplication 1404, but AEP CP 1406 intercepts the message, encapsulatesthe message within an AONP message, and sends the AONP message to an AEPSP 1408, which decapsulates the message from the AONP message and sendsthe message to receiving application 1404. Again, AEP CP 1406 sends anACK to sending application 1402. According to a third route, sendingapplication 1402 sends the message toward receiving application 1404,but AEP SP 1408 intercepts the message and sends the message toreceiving application 1404. In this case, AEP SP 1408 sends an ACK tosending application 1402. Thus, when an AEP intercepts a message, theintercepting AEP sends an ACK to the sending application.

According to one embodiment, AONP is used in node-to-node communicationwith the next hop. In one embodiment, AONP uses HTTP. AONP headers mayinclude HTTP or TCP headers. AONP may indicate RM ACK, QoS level,message priority, and message context (connection, message sequencenumbers, message context identifier, entry node information, etc.). Theactual message payload is in the message body. Asynchronous messagingmay be used between AONS nodes. AONS may conduct route and nodediscovery via static configuration (next hop) and/or via dynamicdiscovery and route advertising (“lazy” discovery).

FIG. 15A and FIG. 15B are diagrams that illustrate a request/responsemessage flow with reliable message delivery. Referring to FIG. 15A, atcircumscribed numeral 1, a sending application 1502 sends a messagetowards a receiving application 1504. At circumscribed numeral 2, an AEPCP 1506 intercepts the message and adds an AONP header to the message,forming an AONP message. At circumscribed numeral 3, AEP CP 1506 savesthe message to a data store 1512. Thus, if there are any problems withsending the message, AEP CP 1506 can resend the copy of the message thatis stored in data store 1512.

At circumscribed numeral 4, AEP CP 1506 sends the AONP message to anAONS router 1508. At circumscribed numeral 5, AONS router 1508 receivesthe AONP message. At circumscribed numeral 6, AONS router 1508 sends theAONP message to an AEP SP 1510. At circumscribed numeral 7, AEP SP 1510receives the AONP message and removes the AONP header from the message,thus decapsulating the message. At circumscribed numeral 8, AEP SP 1510sends the message to receiving application 1504.

At circumscribed numeral 9, AEP SP 1510 sends a reliable messaging (RM)acknowledgement (ACK) to AONS router 1508. At circumscribed numeral 10,AONS router 1508 receives the RM ACK and sends the RM ACK to AEP CP1506. At circumscribed numeral 11, AEP CP 1506 receives the RM ACK and,in response, deletes the copy of the message that is stored in datastore 1512. Because the delivery of the message has been acknowledged,there is no further need to store a copy of the message in data store1512. Alternatively, if AEP CP 1506 does not receive the RM ACK within aspecified period of time, then AEP CP 1506 resends the message.

Referring to FIG. 15B, at circumscribed numeral 12, receivingapplication 1504 sends a response message toward sending application1502. At circumscribed numeral 13, AEP SP 1510 intercepts the messageand adds an AONP header to the message, forming an AONP message. Atcircumscribed numeral 14, AEP SP 1510 sends the AONP message to AONSrouter 1508. At circumscribed numeral 15, AONS router 1508 receives theAONP message. At circumscribed numeral 16, AONS router 1508 sends theAONP message to AEP CP 1506. At circumscribed numeral 17, AEP CP 1506receives the AONP message and removes the AONP header from the message,thus decapsulating the message. At circumscribed numeral 18, AEP CP 1506sends the message to sending application 1502.

FIG. 16 is a diagram that illustrates a one-way message flow withreliable message delivery. At circumscribed numeral 1, a sendingapplication 1602 sends a message towards a receiving application 1604.At circumscribed numeral 2, an AEP CP 1606 intercepts the message andadds an AONP header to the message, forming an AONP message. Atcircumscribed numeral 3, AEP CP 1606 saves the message to a data store1612. Thus, if there are any problems with sending the message, AEP CP1606 can resend the copy of the message that is stored in data store1612. At circumscribed numeral 4, AEP CP 1606 sends an ACK(acknowledgement) back to sending application 1602. At circumscribednumeral 5, AEP CP 1606 sends the AONP message to an AONS router 1608. Atcircumscribed numeral 6, AONS router 1608 receives the AONP message. Atcircumscribed numeral 7, AONS router 1608 sends the AONP message to anAEP SP 1610. At circumscribed numeral 8, AEP SP 1610 receives the AONPmessage and removes the AONP header from the message, thus decapsulatingthe message. At circumscribed numeral 9, AEP SP 1610 sends the messageto receiving application 1604.

At circumscribed numeral 10, AEP SP 1610 sends a reliable messaging (RM)acknowledgement (ACK) to AONS router 1608. At circumscribed numeral 11,AONS router 1608 receives the RM ACK and sends the RM ACK to AEP CP1606. At circumscribed numeral 12, AEP CP 1606 receives the RM ACK and,in response, deletes the copy of the message that is stored in datastore 1612. Because the delivery of the message has been acknowledged,there is no further need to store a copy of the message in data store1612. Alternatively, if AEP CP 1606 does not receive the RM ACK within aspecified period of time, then AEP CP 1606 resends the message. If theresend is not successful within a timeout period, a “delivery-failure”notification message will be send to the original sending application.

FIG. 17 is a diagram that illustrates synchronous request and responsemessages. At circumscribed numeral 1, an AONS node 1704 receives, from aclient 1702, a request message, in either implicit or explicit mode. Atcircumscribed numeral 2, AONS node 1704 reads the message, selects andexecutes a flow, and adds an AONP header to the message. Atcircumscribed numeral 3, AONS node 1704 sends the message to a next hopnode, AONS node 1706. At circumscribed numeral 4, AONS node 1706 readsthe message, selects and executes a flow, and removes the AONP headerfrom the message, formatting the message according to the message formatexpected by a server 1708. At circumscribed numeral 5, AONS node 1706sends the message to the message's destination, server 1708.

At circumscribed numeral 6, AONS node 1706 receives a response messagefrom server 1708 on the same connection on which AONS node 1706 sent therequest message. At circumscribed numeral 7, AONS node 1706 reads themessage, correlates the message with the request message, executes aflow, and adds an AONP header to the message. At circumscribed numeral8, AONS node 1706 sends the message to AONS node 1704. At circumscribednumeral 9, AONS node 1704 reads the message, correlates the message withthe request message, executes a flow, and removes the AONP header fromthe message, formatting the message according to the message formatexpected by client 1702. At circumscribed numeral 10, AONS node 1704sends the message to client 1702 on the same connection on which client1702 sent the request message to AONS node 1704.

FIG. 18 is a diagram that illustrates a sample one-way end-to-endmessage flow. At circumscribed numeral 1, an AONS node 1804 receives,from a client 1802, a request message, in either implicit or explicitmode. At circumscribed numeral 2, AONS node 1804 reads the message,selects and executes a flow, and adds an AONP header to the message. Atcircumscribed numeral 3, AONS node 1804 sends an acknowledgement toclient 1802. At circumscribed numeral 4, AONS node 1804 sends themessage to a next hop node, AONS node 1806. At circumscribed numeral 5,AONS node 1806 reads the message, selects and executes a flow, andremoves the AONP header from the message, formatting the messageaccording to the message format expected by a server 1808. Atcircumscribed numeral 6, AONS node 1806 sends the message to themessage's destination, server 1808.

According to the node view, the message lifecycle within an AONS node,involves ingress/egress processing, message processing, messageexecution control, and flow execution.

FIG. 19 is a diagram that illustrates message-processing modules withinan AONS node 1900. AONS node 1900 comprises an AONS message executioncontroller (AMEC) framework 1902, a policy management subsystem 1904, anAONS message processing infrastructure subsystem 1906, and an AOSS 1908.AMEC framework 1902 comprises a flow management subsystem 1910, abladelet™ execution subsystem 1912, and a message execution controller1914. Policy management subsystem 1904 communicates with flow managementsubsystem 1910. AOSS 1908 communicates with bladelet™ executionsubsystem 1912 and AONS message processing infrastructure subsystem1906. AONS message processing infrastructure subsystem 1906 communicateswith message execution controller 1914. Flow management subsystem 1910,bladelet™ execution subsystem, and message execution controller 1914 allcommunicate with each other.

FIG. 20 is a diagram that illustrates message processing within AONSnode 1900. AMEC framework 1902 is an event-based multi-threadedmechanism to maximize throughput while minimizing latency for messagesin the AONS node. According to one embodiment, received packets arere-directed, TCP termination is performed, SSL termination is performedif needed, Layer 5 protocol adapter and access method processing isperformed (using access methods such as HTTP, SMTP, FTP, JMS/MQ, JMS/RV,JDBC, etc.), AONS messages (normalized message format for internal AONSprocessing) are formed, messages are queued, messages are dequeued basedon processing thread availability, a flow (or rule) is selected, theselected flow is executed, the message is forwarded to the message'sdestination, and for request/response-based semantics, responses arehandled via connection/session state maintained within AMEC framework1902.

In one embodiment, executing the flow comprises executing each step(i.e., bladelet™/action) of the flow. If a bladelet™ is to be run withina separate context, then AMEC framework 1902 may enqueue intobladelet™-specific queues, and, based on thread availability, dequeueappropriate bladelet™ states from each bladelet™ queue.

-   -   3.5.10 Flows, Bladelets™, and Scriptlets™

According to one embodiment, flows string together bladelets™ (i.e.,actions) to customize message processing logic. Scriptlets™ provide amechanism for customers and partners to customize or extend native AONSfunctionality. Some bladelets™ and services may be provided with an AONSnode.

-   -   3.5.11 AONS Services

As mentioned in the previous section, a set of core services may beprovided by AONS to form the underlying foundation of value-addedfunctionality that can be delivered via an AONS node. In one embodiment,these include: Security Services, Standard Compression Services, DeltaCompression Services, Caching Service, Message Logging Service, PolicyManagement Service (Policy Manager), Reliable Messaging Service,Publish/Subscribe Service, Activity Monitoring Service, MessageDistribution Service, XML Parsing Service, XSLT Transformation Service,and QoS Management Service. In one embodiment, each AONS core service isimplemented within the context of a service framework.

-   -   3.5.12 AONS Configuration and Management

In one embodiment, an AONS node is provisioned and configured for aclass of application messages, where it enforces the policies that aredeclaratively defined on behalf-of the application end-points,business-domains, security-domains, administrative domains, andnetwork-domains. Furthermore, the AONS node promotes flexiblecomposition and customization of different product functional featuresby means of configurability and extensibility of different software andhardware sub-systems for a given deployment scenario. Due to theapplication and network embodiments of the AONS functionality, the AONSarchitecture framework should effectively and uniformly addressdifferent aspects of configurability, manageability, and monitorabilityof the various system components and their environments.

The AONS Configuration and Management framework is based upon fivefunctional areas (“FCAPS”) for network management as recommended by theISO network management forum. The functional areas include faultmanagement, configuration management, accounting management, performancemanagement, and security management. Fault management is the process ofdiscovering, isolating, and fixing the problems or faults in the AONSnodes. Configuration management is the process of finding and setting upthe AONS nodes. Accounting management involves tracking usage andutilization of AONS resources to facilitate their proper usage.Performance management is the process of measuring the performance ofthe AONS system components and the overall system. Security managementcontrols access to information on the AONS system. Much of the abovefunctionality is handled via proper instrumentation, programminginterfaces, and tools as part of the overall AONS solution.

FIG. 21, FIG. 22, and FIG. 23 are diagrams that illustrate entitieswithin an AONS configuration and management framework. An AONSmanagement console (AMC) is the centralized hub for configuration andmanagement of AONS policies, flows, scriptlets™ and other manageableentities. Configurable data is pushed to the AMC from an AONS designstudio (flow tool) and the AONS admin may then provision this data tothe production deployment. A promotion process is also provided to testand validate changes via a development to staging/certification toproduction rollout process. An AONS management agent (AMA) resides onindividual AONS blades and provides the local control and dispatchcapabilities for AONS. The AMA interacts with the AMC to get updates.The AMA takes appropriate actions to implement changes. The AMA is alsoused for collecting monitoring data to report to third party consoles.

-   -   3.5.13 AONS Monitoring

In one embodiment, AONS is instrumented to support well-defined eventsfor appropriate monitoring and visibility into internal processingactivities. The monitoring of AONS nodes may be accomplished via apre-defined JMX MBean agent that is running on each AONS node. Thisagent communicates with a remote JMX MBean server on the PC complex. AnAONS MIB is leveraged for SNMP integration to third party consoles. FIG.24 is a diagram that illustrates an AONS monitoring architecture.

-   -   3.5.14 AONS Tools

In one embodiment, the following tool sets are provided for variousfunctional needs of AONS: a design studio, an admin studio, and amessage log viewer. The design studio is a visual tool for designingflows and applying message classification and mapping policies. Theadmin studio is a web-based interface to perform all administration andconfiguration functions. The message log viewer is a visual interface toanalyze message traffic, patterns, and trace information.

4.0 Implementation Mechanisms—Hardware Overview

FIG. 5 is a block diagram that illustrates a computer system 500 uponwhich an embodiment of the invention may be implemented. The preferredembodiment is implemented using one or more computer programs running ona network element such as a proxy device. Thus, in this embodiment, thecomputer system 500 is a proxy device such as a load balancer.

Computer system 500 includes a bus 502 or other communication mechanismfor communicating information, and a processor 504 coupled with bus 502for processing information. Computer system 500 also includes a mainmemory 506, such as a random access memory (RAM), flash memory, or otherdynamic storage device, coupled to bus 502 for storing information andinstructions to be executed by processor 504. Main memory 506 also maybe used for storing temporary variables or other intermediateinformation during execution of instructions to be executed by processor504. Computer system 500 further includes a read only memory (ROM) 508or other static storage device coupled to bus 502 for storing staticinformation and instructions for processor 504. A storage device 510,such as a magnetic disk, flash memory or optical disk, is provided andcoupled to bus 502 for storing information and instructions.

A communication interface 518 may be coupled to bus 502 forcommunicating information and command selections to processor 504.Interface 518 is a conventional serial interface such as an RS-232 orRS-322 interface. An external terminal 512 or other computer systemconnects to the computer system 500 and provides commands to it usingthe interface 514. Firmware or software running in the computer system500 provides a terminal interface or character-based command interfaceso that external commands can be given to the computer system.

A switching system 516 is coupled to bus 502 and has an input interface514 and an output interface 519 to one or more external networkelements. The external network elements may include a local network 522coupled to one or more hosts 524, or a global network such as Internet528 having one or more servers 530. The switching system 516 switchesinformation traffic arriving on input interface 514 to output interface519 according to pre-determined protocols and conventions that are wellknown. For example, switching system 516, in cooperation with processor504, can determine a destination of a packet of data arriving on inputinterface 514 and send it to the correct destination using outputinterface 519. The destinations may include host 524, server 530, otherend stations, or other routing and switching devices in local network522 or Internet 528.

The invention is related to the use of computer system 500 for avoidingthe storage of client state on computer system 500. According to oneembodiment of the invention, computer system 500 provides for suchupdating in response to processor 504 executing one or more sequences ofone or more instructions contained in main memory 506. Such instructionsmay be read into main memory 506 from another computer-readable medium,such as storage device 510. Execution of the sequences of instructionscontained in main memory 506 causes processor 504 to perform the processsteps described herein. One or more processors in a multi-processingarrangement may also be employed to execute the sequences ofinstructions contained in main memory 506. In alternative embodiments,hard-wired circuitry may be used in place of or in combination withsoftware instructions to implement the invention. Thus, embodiments ofthe invention are not limited to any specific combination of hardwarecircuitry and software.

The term “computer-readable medium” as used herein refers to any mediumthat participates in providing instructions to processor 504 forexecution. Such a medium may take many forms, including but not limitedto, non-volatile media, volatile media, and transmission media.Non-volatile media includes, for example, optical or magnetic disks,such as storage device 510. Volatile media includes dynamic memory, suchas main memory 506. Transmission media includes coaxial cables, copperwire and fiber optics, including the wires that comprise bus 502.Transmission media can also take the form of acoustic or light waves,such as those generated during radio wave and infrared datacommunications.

Common forms of computer-readable media include, for example, a floppydisk, a flexible disk, hard disk, magnetic tape, or any other magneticmedium, a CD-ROM, any other optical medium, punch cards, paper tape, anyother physical medium with patterns of holes, a RAM, a PROM, and EPROM,a FLASH-EPROM, any other memory chip or cartridge, a carrier wave asdescribed hereinafter, or any other medium from which a computer canread.

Various forms of computer readable media may be involved in carrying oneor more sequences of one or more instructions to processor 504 forexecution. For example, the instructions may initially be carried on amagnetic disk of a remote computer. The remote computer can load theinstructions into its dynamic memory and send the instructions over atelephone line using a modem. A modem local to computer system 500 canreceive the data on the telephone line and use an infrared transmitterto convert the data to an infrared signal. An infrared detector coupledto bus 502 can receive the data carried in the infrared signal and placethe data on bus 502. Bus 502 carries the data to main memory 506, fromwhich processor 504 retrieves and executes the instructions. Theinstructions received by main memory 506 may optionally be stored onstorage device 510 either before or after execution by processor 504.

Communication interface 518 also provides a two-way data communicationcoupling to a network link 520 that is connected to a local network 522.For example, communication interface 518 may be an integrated servicesdigital network (ISDN) card or a modem to provide a data communicationconnection to a corresponding type of telephone line. As anotherexample, communication interface 518 may be a local area network (LAN)card to provide a data communication connection to a compatible LAN.Wireless links may also be implemented. In any such implementation,communication interface 518 sends and receives electrical,electromagnetic or optical signals that carry digital data streamsrepresenting various types of information.

Network link 520 typically provides data communication through one ormore networks to other data devices. For example, network link 520 mayprovide a connection through local network 522 to a host computer 524 orto data equipment operated by an Internet Service Provider (ISP) 526.ISP 526 in turn provides data communication services through theworldwide packet data communication network now commonly referred to asthe “Internet” 528. Local network 522 and Internet 528 both useelectrical, electromagnetic or optical signals that carry digital datastreams. The signals through the various networks and the signals onnetwork link 520 and through communication interface 518, which carrythe digital data to and from computer system 500, are exemplary forms ofcarrier waves transporting the information.

Computer system 500 can send messages and receive data, includingprogram code, through the network(s), network link 520 and communicationinterface 518. In the Internet example, a server 530 might transmit arequested code for an application program through Internet 528, ISP 526,local network 522 and communication interface 518. In accordance withthe invention, one such downloaded application provides for avoiding thestorage of client state on a server as described herein.

Processor 504 may execute the received code as it is received and/orstored in storage device 510 or other non-volatile storage for laterexecution. In this manner, computer system 500 may obtain applicationcode in the form of a carrier wave.

5.0 Extensions and Alternatives

In the foregoing specification, the invention has been described withreference to specific embodiments thereof. It will, however, be evidentthat various modifications and changes may be made thereto withoutdeparting from the broader spirit and scope of the invention. Thespecification and drawings are, accordingly, to be regarded in anillustrative rather than a restrictive sense.

1. A method, comprising the computer-implemented steps of: intercepting,at a network element, one or more data packets comprising network layeror transport layer headers having an address of a destination thatdiffers from the network element; determining whether informationcontained in one or more layer 2-4 headers of the one or more datapacket satisfies specified criteria; in response to determining that theinformation satisfies the specified criteria, directing the one or moredata packets to a blade of the network element that performs processingbased on at least a portion of an application layer message that is atleast partially contained in the one or more data packets; in responseto determining that the information does not satisfy the specifiedcriteria, forwarding the one or more data packets towards thedestination without sending the one or more data packets to the blade.2. A method as recited in claim 1, wherein the information comprises oneor more of a source IP address and a destination IP address.
 3. A methodas recited in claim 1, wherein the information comprises one or more ofa source TCP port and a destination TCP port.
 4. A method as recited inclaim 1, further comprising: determining, based on the portion of theapplication layer message, a particular message classification;determining one or more actions with which the particular messageclassification is associated in response to a determination that theparticular message classification is associated with the one or moreactions.
 5. A method as recited in claim 1, further comprising, based onthe portion of the application layer message, performing one or moreactions on behalf of the application.
 6. A method as recited in claim 5,further comprising sending, from the network element, one or more seconddata packets that contain a modified application layer message; whereinat least one of the one or more actions comprises modifying the portionof the application layer message to produce the modified applicationlayer message.
 7. A method as recited in claim 5, further comprisingreceiving user-specified input at the network element, wherein theuser-specified input indicates an order in which the one or more actionsare to be performed; wherein performing the one or more actionscomprises performing the one or more actions in the order.
 8. A methodas recited in claim 5, further comprising: receiving user-specifiedinput at the network element, wherein the user-specified input indicatesone or more criteria; determining whether the portion of the applicationlayer message satisfies the one or more criteria; wherein performing theone or more actions comprises performing the one or more actions thatare associated with the one or more criteria.
 9. A method as recited inclaim 5, wherein determining whether the portion of the applicationlayer message satisfies the one or more criteria comprises determiningwhether a specified string of text occurs within the portion of theapplication layer message.
 10. A method as recited in claim 5, whereinthe portion of the application layer message is formatted in ExtensibleMarkup Language (XML), and wherein determining whether the portion ofthe application layer message satisfies the one or more criteriacomprises determining whether a specified path occurs within the portionof the application layer message.
 11. A method as recited in claim 5,wherein at least one of the one or more actions comprises preventing theone or more data packets from being delivered to the destination.
 12. Amethod as recited in claim 1, further comprising sending, to a sourcefrom which the one or more data packets originated, a response that iscached at the network element.
 13. A method as recited in claim 1,wherein the network element is a network switch or router.
 14. A methodas recited in claim 1, wherein the network element is a proxy device.15. A method as recited in claim 1, further comprising modifying theportion of the application layer message so that the portion of theapplication layer message is formatted in an application layer messageformat that differs from an application layer message format in whichthe portion of the application layer message was formatted when the oneor more data packets were received at the network element.
 16. A methodas recited in claim 1, further comprising processing, at the networkelement, a message that is not destined for the device that hosts theapplication.
 17. A method as recited in claim 1, further comprising:determining whether the portion of the message will cause an entity tofail if the entity receives the message; in response to a determinationthat the portion of the message will cause the entity to fail if theentity receives the message, performing one or more specified actions.18. A method as recited in claim 1, further comprising performing, atthe network element, an operation on a message that is a requestmessage, a response message, an exception processing message, or amessage that was not sent between a client application and a serverapplication.
 19. A method as recited in claim 1, further comprisingmodifying one or more headers associated with the one or more datapackets so that the one or more data packets are destined for one ormore destinations that include a second destination that differs fromthe first destination.
 20. A method as recited in claim 1, wherein theapplication layer message comprises a multi-part MIME message, andfurther comprising handling each part of the multi-part MIME messageseparately and independently from each other part of the multi-part MIMEmessage.
 21. A computer-readable volatile or non-volatile storage mediumstoring one or more sequences of instructions, which instructions, whenexecuted by one or more processors, cause the one or more processors tocarry out the steps of: intercepting, at a network element, one or moredata packets comprising network layer or transport layer headers havingan address of a destination that differs from the network element;determining whether information contained in one or more layer 2-4headers of the one or more data packet satisfies specified criteria; inresponse to determining that the information satisfies the specifiedcriteria, directing the one or more data packets to a blade of thenetwork element that performs processing based on at least a portion ofan application layer message that is at least partially contained in theone or more data packets; in response to determining that theinformation does not satisfy the specified criteria, forwarding the oneor more data packets towards the destination without sending the one ormore data packets to the blade.
 22. A computer-readable volatile ornon-volatile storage medium as recited in claim 21, wherein the one ormore sequences of instructions further comprise instructions, whichinstructions, when executed by one or more processors, cause the one ormore processors to carry out the steps of: determining, based on theportion of the application layer message, a particular messageclassification; determining one or more actions with which theparticular message classification is associated in response to adetermination that the particular message classification is associatedwith the one or more actions.
 23. A computer-readable volatile ornon-volatile storage medium as recited in claim 21, wherein the one ormore sequences of instructions further comprise instructions, whichinstructions, when executed by one or more processors, cause the one ormore processors to carry out the step of, based on the portion of theapplication layer message, performing one or more actions on behalf ofthe application.
 24. A computer-readable volatile or non-volatilestorage medium as recited in claim 21, wherein the one or more sequencesof instructions further comprise instructions, which instructions, whenexecuted by one or more processors, cause the one or more processors tocarry out the steps of: modifying the portion of the application layermessage to produce the modified application layer message; sending, fromthe network element, one or more second data packets that contain amodified application layer message; wherein at least one of the one ormore actions comprises.